Pharma Notes: Gastrointestinal Medications & Pathophysiology of the Stomach PDF

# Pharma Notes: Gastrointestinal Medications and Pathophysiology of the Stomach ## Pathophysiology of the Stomach: ### Cell Types: - Parietal cells - Chief cells - Surface epithelium cells ### Functions: - **Surface Epithelium Cells:** - Secrete mucus for protection. - **Parietal Cells:**...

# Pharma Notes: Gastrointestinal Medications and Pathophysiology of the Stomach ## Pathophysiology of the Stomach: ### Cell Types: - Parietal cells - Chief cells - Surface epithelium cells ### Functions: - **Surface Epithelium Cells:** - Secrete mucus for protection. - **Parietal Cells:** - Produce hydrochloric acid (HCl) and intrinsic factor (for vitamin B12 absorption). - **Chief Cells:** - Secrete pepsinogen, converted to pepsin for digestion. - **Enteroendocrine Cells and G Cells:** - Secrete various substances, including gastrin. ### Imbalance: - Acid-related disorders result from secretion imbalances. ## Common Conditions: - GERD (gastroesophageal reflux disease) - PUD (peptic ulcer disease) ## Nursing Considerations for Hyperacidity ### Medications: ### Assessments: - Abdominal assessment and bowel pattern documentation - Monitor for medication interactions, side effects, and vitamin B12 malabsorption ### Implementation: - Follow drug label information - Consider cultural preferences - Modify care plans for safe use with alternative methods ### Evaluation: - Monitor symptom improvement - Notify the provider if no improvement or worsening occurs ## Hyperacidity Medication Classes: ### 1. Antacids - **Indications:** Heartburn, acid indigestion, upset stomach - **Mechanism:** Neutralize gastric acidity, elevate stomach pH, and inactivate pepsin - **Example:** Calcium carbonate - **Administration Considerations:** - Various formulations (tablet, chewable, liquid) - Caution with kidney disease - **Patient Teaching:** ### 2. H2-Receptor Antagonist (Famotidine) - **Indications:** GERD, peptic ulcer, erosive esophagitis, hypersecretory conditions - **Mechanism:** Blocks histamine's action, reducing hydrochloric acid production - **Administration Considerations:** - Take 15-60 minutes before potential heartburn triggers - Dosage adjustment for liver/kidney disease - **Patient Teaching:** - Shake oral suspension - Encourage fluids and a high-fiber diet ### 3. Proton Pump Inhibitors (Pantoprazole) - **Indications:** GERD, excess stomach acid, Zollinger-Ellison syndrome - **Mechanism:** Inhibit hydrogen-potassium ATPase, reducing hydrochloric acid - **Administration Considerations:** - Oral, NG tube, IV - Mix granules with applesauce or apple juice - **Patient Teaching:** - Call provider if no improvement or worsening - Discourage alcohol, NSAIDs, and irritating foods ### 4. Mucosal Protectant (Sucralfate) - **Indications:** Treatment of ulcers - **Mechanism:** Locally covers and protects ulcer sites - **Administration Considerations:** - Administer on an empty stomach - Cautious use in chronic renal failure - **Patient Teaching:** - Call provider if no improvement or worsening ### 5. Antiflatulent (Simethicone) - **Indications:** Relief of gas discomfort - **Mechanism:** Alters elasticity of gas bubbles, facilitating expulsion - **Administration Considerations:** - Usually taken four times a day - Shake liquid drops before administering - **Patient Teaching:** - Educate on additional measures for gas expulsion. ## Antidiarrheals: - **Various causes:** bacteria, viruses, parasites, medications, food intolerances, and diseases. - **Severe threat:** Dehydration due to water and electrolyte loss. ## Nursing Considerations: ### 1. Assessment: - Abdominal assessment, bowel movement frequency, stool characteristics, and skin breakdown. - Priority on monitoring dehydration, especially in vulnerable populations. ### 2. Implementation: - Caution against exceeding OTC medication dosages. - Advocacy for probiotics use. - Nonpharmacological interventions: fluid replacement, soft foods. ### 3. Evaluation: - Notify provider if symptoms persist after 48 hours. - Monitor for adverse effects: increased bleeding, abnormal heart rhythms. ## Medication Classes: ### 1. Adsorbents (e.g., Bismuth Subsalicylate) - **Mechanism:** Coats GI tract, binds causative bacteria/toxins, decreases fluid flow. - **Administration Considerations:** - Avoid in salicylate allergy, ulcer, bleeding, or black stool. - Patient Teaching: Take as directed, be aware of color changes, discontinue on tinnitus ### 2. Antimotility: - **Anticholinergics (e.g., Hyoscyamine)** - **Mechanism:** Inhibits propulsive motility, decreases gastric acid secretion. - **Administration Considerations:** - Contraindications: glaucoma, myasthenia gravis. - Patient Teaching: May cause dizziness, drowsiness, alleviate dry mouth with oral hygiene. - **Opioid-Like Medication (e.g., Loperamide)** - **Mechanism:** Decreases fluid flow, slows bowel movement. - **Administration** ### 3. Probiotics (e.g., Lactobacillus) - **Mechanism:** Replenishes normal bacterial flora in the Gl tract. - **Administration Considerations:** Mild side effects (gas, bloating), safe for children ## Nausea and Vomiting: ### Definition: - **Nausea:** Unpleasant urge to vomit - **Vomiting (emesis):** Forceful expulsion of gastric contents ### Causes: - Morning sickness (pregnancy) - Infections (gastroenteritis) - Migraines - Motion sickness - Medication side effects - Food poisoning - GERD, ulcers - Intestinal obstruction - Poisoning or exposure - Diseases in other organs (cardiac, renal, liver) ### Serious Conditions: - Vomiting > 24 hours - Blood in vomit (hematemesis) - Severe abdominal pain - Severe headache, stiff neck - Signs of dehydration ### Pathophysiology of Nausea and Vomiting: - **Vomiting Center (VC):** - Activated by irritants or input from the gastrointestinal tract, cerebral cortex, vestibular region, and chemoreceptor trigger zone (CTZ). - CTZ not restricted by blood-brain barrier, responds to toxins in bloodstream. - Receives stimuli from various locations in the body. - **Chemoreceptor Trigger Zone (CTZ):** - Located in the area postrema in the brain. - Not restricted by blood-brain barrier. - Responds directly to toxins in the bloodstream. - Receives stimuli from vestibular center, visceral organs, thalamus, cerebral cortex. - **Vestibular Center and Cerebral Cortex:** - Vestibular system (inner ear) contributes to motion sickness-related nausea. - Gastrointestinal tract sends stimuli via cranial nerves IX and X. - Cerebral cortex responds to odors, tastes, images, sending stimuli to CTZ. ### Vomiting Process: - VC initiates vomiting by inhibiting peristalsis. - Produces retro-peristaltic contractions. - Autonomic stimulation causes symptoms like salivation, pallor, sweating, tachycardia. - Involves various neurotransmitters. ## Medication Classes and Mechanisms: ### 1. Anticholinergics - **Example:** Scopolamine - **Mechanism:** - Blocks ACh receptors in vestibular system. - Dries GI secretions, reduces smooth muscle spasms. - **Administration:** - Transdermal patch for continuous release. - **Considerations:** - Contraindicated in glaucoma. - Monitor for anticholinergic side effects. ### 2. Antihistamines - **Example:** Meclizine - **Mechanism:** - Blocks H1 receptors in vestibular center. - May block acetylcholine. - **Administration:** - Contraindicated in glaucoma. - **Considerations:** - Dosage before travel. - May cause drowsiness. ### 3. Dopamine Antagonists - **Example:** Prochlorperazine - **Mechanism:** - Blocks dopamine in CTZ. - Calms the central nervous system. - **Administration:** - Oral, intramuscular, rectal, intravenous. - **Considerations:** - Avoid in children under 2. - Monitor for side effects. ### 4. Prokinetics - **Example:** Metoclopramide - **Mechanism:** - Promotes peristalsis, reduces nausea. - **Administration:** - Oral, intramuscular, intravenous. - **Considerations:** - Contraindications in certain conditions. - Monitor for adverse reactions. ### 5. Serotonin Antagonists - **Example:** Ondansetron - **Mechanism:** - Blocks serotonin in GI tract, CTZ, VC. - **Administration:** - Oral, injectable. - **Considerations:** - Contraindicated with apomorphine. - Monitor for side effects, QT prolongation. ### 6. Neurokinin Receptor Antagonists - **Example:** Aprepitant - **Mechanism:** - Inhibits substance-P neurokinin receptors. - **Administration:** - Oral, intravenous. - **Considerations:** - Administered with dexamethasone, ondansetron. - CYP3A4 drug interactions. ### 7. Tetrahydrocannabinoids (THC) - **Example:** Dronabinol/Medical Marijuana - **Mechanism:** - Inhibitory effects in the cerebral cortex. - Alters mood, perception, relieves nausea. - **Administration:** - Oral, controlled substance. - **Considerations:** - Caution in elderly patients. - Dose-related "high." ### Herbal and Vitamin Supplements - **Ginger:** - Used traditionally as an antiemetic. - Antagonizes 5HT, cholinergic receptors. - Considerations for reflux, heartburn, bleeding. - **Pyridoxine (Vitamin B6):** - Recommended for nausea in <2, potential abnormal heart rhythm. - Patient Teaching: Take as directed, avoid alcohol, may cause drowsiness. ## Respiratory Medications ### Antihistamines: - **Examples:** - First-generation: Diphenhydramine - Second-generation: Cetirizine - **Mechanism of Action:** - Blocks histamine at H1 receptors. - Inhibits smooth muscle constriction. - Decreases capillary permeability, salivation, and tear formation. - **Indications:** - Relief of allergy or cold symptoms. - **Nursing Considerations:** - Not safe for children under 2 years without a healthcare provider’s order. - Caution in the elderly with first-generation antihistamines. - **Adverse/Side Effects:** - First-generation: Anticholinergic effects, CNS depression or stimulation. - Second-generation: Headache, nausea, vomiting, fatigue. - **Patient Teaching:** - May cause drowsiness; avoid alcohol and CNS depressants. - Take the recommended amount; be cautious about side effects like dry mouth. ### Expectorants: - **Example:** Guaifenesin - **Mechanism of Action:** Reduces viscosity of respiratory secretions. - **Indication:** Productive cough, loosening mucus. - **Nursing Considerations:** Safe for all ages. - **Adverse/Side Effects:** Skin rash, headache, nausea, vomiting. - **Patient Teaching:** Avoid irritants; may cause drowsiness; avoid with CNS depressants. ### BETA-2 AGONIST: - **Examples:** - Short-acting: Albuterol - Long-acting: Salmeterol - **Mechanism of Action:** Stimulates Beta 2-adrenergic receptors for bronchodilation. - **Indications:** - Albuterol for bronchospasm. - Salmeterol for bronchospasm prevention. - **Adverse/Side Effects:** Muscle tremor, cardiac stimulation, CNS stimulation. - **Patient Teaching:** - Take as directed; report sustained or worsening symptoms. - Rinse mouth after albuterol use; understand usage of short-acting and long-acting inhalers. ### Corticosteroids - **Examples:** - Inhaled: Fluticasone - Oral: Prednisone - IV: Methylprednisolone - **Mechanism of Action:** Anti-inflammatory and immune modulation. - **Indications:** - Fluticasone for asthma control; - Prednisone and Methylprednisolone for severe allergic conditions. - **Adverse/Side Effects:** - Fluticasone: Hoarseness, dry mouth, candidiasis. - Prednisone and Methylprednisolone: Varied systemic effects. - **Patient Teaching:** - Not for acute asthma attacks; may cause immunosuppression and varied side effects. ### Leukotriene Receptor Antagonists: - **Example:** Montelukast - **Mechanism of Action:** Blocks leukotriene receptors; decreases inflammation. - **Indications:** - Long-term control of asthma, prevention of asthma attacks, exercise-induced bronchospasm, allergic rhinitis. - **Adverse/Side Effects:** Headache, cough, nasal congestion, nausea, hepatotoxicity. - **Patient Teaching:** - Take as directed; not as a rescue medication; notify healthcare provider before discontinuation. ## Cardiology medications ### Antiarrhythmics: - **Introduction:** - Arrhythmia: Deviation from normal heartbeat rate or pattern. - ECG: Identifies and monitors arrhythmias. - **Overview:** Medications regulate heart rate and rhythm. - **Risk:** All carry the risk of producing arrhythmias. ### Class I - Sodium Channel Blockers: - **Subgroups:** IA, IB, IC - **Examples:** Quinidine (IA), Lidocaine (IB), Flecainide (IC) - **Mechanism:** Slows conduction, prolongs depolarization. ### Class II - Beta Blockers: - **Examples:** Sotalol (also Class III), Metoprolol. - **Mechanism (Sotalol):** Non-selective beta-adrenergic blocker. Also can be consider as Type III: (Prolongs repolarization by blocking potassium channels.) ### Class III - Potassium Channel Blockers: - **Example:** Amiodarone. - **Mechanism:** Prolongs repolarization by blocking potassium channels. - **Indications for Amiodarone:** Life-threatening recurrent ventricular arrhythmias. ### Class IV - Calcium Channel Blockers: - **Examples:** Verapamil, Diltiazem - **Verapamil:** - antiarrhythmic and commonly used to control heart rate associated with supraventricular tachycardias is Verapamil. - **Diltiazem:** - Class IV antiarrhythmic, inhibits calcium during depolarization. - (Blocks/Stops Calcium during heartbeats.) ### Quinidine: - **Nursing Considerations:** - Contraindications: Thrombocytopenia, myasthenia gravis. - Adverse Effects: Prolonged QT interval, thrombocytopenia. ### Adenosine: - **Mechanism:** Slows conduction through AV node. - **Indications:** Paroxysmal supraventricular tachycardia. - **Nursing Considerations:** - Contraindications: 2nd or 3rd degree AV block. - Adverse Effects: Prolonged asystole, facial flushing. ### Cardiac Glycosides: - **Digoxin:** - Mechanism: Inhibits sodium and potassium pump, increases intracellular sodium. - Indications: Heart failure, atrial fibrillation. - **Digoxin:** - Nursing Considerations: - Monitor apical pulse, serum digoxin, potassium levels. - Adverse Effects: Digoxin toxicity, GI symptoms. ### Antianginals - Nitrates: - **Introduction:** - Angina Pectoris: Chest pain due to inadequate blood flow. - Antianginals: Increase blood flow to the heart or decrease oxygen demand. ### Nitrates: - **Mechanism of Action:** Nitroglycerin relaxes vascular smooth muscle. - **Indications for Use:** Relief of angina due to coronary artery disease. - **Nursing Considerations Across the Lifespan:** - Contraindications: Patients on sildenafil, pregnant/breastfeeding - Adverse Effects: Hypotension, headache, ### Diuretics: - **Introduction:** - Purpose: Decrease blood pressure, alleviate edema. - Classifications: Loop, Thiazide, Potassium-sparing, Osmotic diuretics. ### Loop Diuretic - Furosemide: - **Mechanism:** Inhibits sodium and chloride absorption. - **Indications:** Treats edema, manages hypertension. - **Nursing Considerations:** - Onset of diuresis: Within 1 hour. - Adverse Effects: Dehydration, hypotension. ### Thiazide Diuretic - Hydrochlorothiazide: - **Mechanism:** Promotes sodium and water excretion. - **Indications:** Manages hypertension, edema. - **Nursing Considerations:** - Contraindicated: Anuria, severe renal disease. - Adverse Effects: Electrolyte depletion, weakness. ### Potassium-Sparing Diuretic - Spironolactone: - **Mechanism:** Competitive binding of receptors, retains potassium. - **Indications:** Treats hypertension, controls edema. - **Nursing Considerations:** - Adverse Effects: Hyperkalemia, hyperglycemia. - Administer in the morning. ### Antihypertensives: - **Introduction:** - Purpose: Treat hypertension, different mechanisms. - Classes: Alpha-2 Agonist (Clonidine), Beta Blockers, ACE Inhibitor, ARB. ### Alpha-2 Agonist - Clonidine: - **Mechanism:** Stimulates alpha-adrenergic receptors. ### Beta Blocker - Metoprolol: - **Mechanism:** Blocks Beta-1 receptors, decreases heart rate. - **Indications:** Treats high blood pressure, chest pain. - **Nursing Considerations:** - ER formulations should not be crushed. - Assess apical pulse rate before administering. ### Hydralazine: - **Direct vasodilator, relaxes vascular smooth muscle.** ### ACE Inhibitor - Captopril: - **Mechanism:** Blocks conversion of Angiotensin I to Angiotensin II. - **Indications:** Treats hypertension, heart failure. - **Nursing Considerations:** - Contraindicated in pregnancy. - Use with caution in diabetic patients. ### ARB - Losartan: - **Mechanism:** Blocks Angiotensin II. - **Indications:** Treats hypertension, prevents nephropathy. - **Nursing Considerations:** - Avoid in pregnant patients. - Anticipate dosage adjustment with hepatic impairment. - **Patient Teaching & Education:** - Do not discontinue therapy without direction. - May cause orthostatic changes. ### Antilipemics: - **Introduction:** - Purpose: Reduce hyperlipidemia. - Medications: Atorvastatin, Ezetimibe. ### Atorvastatin: - **Mechanism:** Inhibits HMG-CoA reductase, reduces LDL. - **Indications:** Hyperlipidemia, prevention of cardiovascular disease. - **Nursing Considerations:** - Contraindications: Hepatic disease, pregnancy. - Adverse Effects: Myalgia, muscle spasms. - **Patient Teaching & Education:** - Take at the same time each day. - Report muscle weakness, abdominal pain. ### Ezetimibe: - **Indications:** Hyperlipidemia, familial hypercholesterolemia. - **Nursing Considerations:** - Use with caution when combined with other medications. - **Patient Teaching & Education:** - Take at the same time each day. - Report muscle weakness, abdominal pain. ### Blood Coagulation Modifiers: ### Anticoagulants: - **Heparin Sodium:** - **Mechanism:** Inhibits activated coagulation factors. - **Indications:** DVT, pulmonary embolism. - **Nursing Considerations:** - Reversal: Protamine sulfate. - Monitor for bleeding, especially in >60. - **Patient Teaching & Education:** - Report bleeding/bruising promptly. - Avoid aspirin/NSAIDs. - **Low Molecular Weight Heparin (LMWH) - Enoxaparin:** - **Mechanism:** Higher anti-Factor Xa to anti-Factor Ila activity. - **Indications:** Prevention/treatment of DVT. - **Nursing Considerations:** - Caution in renal impairment. - Overdosage neutralized with protamine sulfate. - **Patient Teaching & Education:** - Report bleeding/bruising promptly. - Avoid aspirin/NSAIDs. - **Warfarin:** - **Mechanism:** Inhibits synthesis of vitamin K-dependent clotting factors. - **Indications:** Venous thrombosis, pulmonary embolism. - **Nursing Considerations:** - Contraindicated in pregnancy, reversible with vitamin K. - Close monitoring of PT or INR. - **Patient Education:** - Avoid alcohol, cranberries, grapefruit. - Adhere strictly to prescribed dosage. ### Study Highlights ### Class I - Sodium Channel Blockers: - **Examples:** Quinidine (IA), Lidocaine (IB), Flecainide (IC). - **Mechanism:** Slows conduction, prolongs depolarization. ### Class II - Beta Blockers: - **Examples:** Sotalol (also Class III), Metoprolol. - **Mechanism (Sotalol):** Non-selective beta-adrenergic blocker. Also can be consider as Type III: (Prolongs repolarization by blocking potassium channels.) ### Class III - Potassium Channel Blockers: - **Example:** Amiodarone. - **Mechanism:** Prolongs repolarization by blocking potassium channels. - **Indications for Amiodarone:** Life-threatening recurrent ventricular arrhythmias. ### Class IV - Calcium Channel Blockers: - **Examples:** Verapamil, Diltiazem - **Verapamil:** - antiarrhythmic and commonly used to control heart rate associated with supraventricular tachycardias is Verapamil. - **Diltiazem:** - Class IV antiarrhythmic, inhibits calcium during depolarization. - (Blocks/Stops Calcium during heartbeats.) ### Quinidine: - **Nursing Considerations:** - Contraindications: Thrombocytopenia, myasthenia gravis. - Adverse Effects: Prolonged QT interval, thrombocytopenia. ### Adenosine: - **Mechanism:** Slows conduction through AV node. - **Indications:** Paroxysmal supraventricular tachycardia. - **Nursing Considerations:** - Contraindications: 2nd or 3rd degree AV block. - Adverse Effects: Prolonged asystole, facial flushing. ### Cardiac Glycosides: - **Digoxin:** - Mechanism: Inhibits sodium and potassium pump, increases intracellular sodium. - Indications: Heart failure, atrial fibrillation. ### Diuretics: - **Loop Diuretic - Furosemide:** - **Mechanism:** Inhibits sodium and chloride absorption. - **Indications:** Treats edema, manages hypertension. - **Nursing Considerations:** - Onset of diuresis: Within 1 hour. - Adverse Effects: Dehydration, hypokalemia. ### Antihypertensives: - **Alpha-2 Agonist - Clonidine:** - **Mechanism:** Stimulates alpha-adrenergic receptors. - **Indications:** Treats hypertension, ADHD. - **Nursing Considerations:** - Dosage adjusted to patient's BP. - Caution: Higher bleeding incidence in >60. ### Beta Blocker - Metoprolol: - **Mechanism:** Blocks Beta-1 receptors, decreases heart rate. - **Indications:** Treats high blood pressure, chest pain. - **Nursing Considerations:** - ER formulations should not be crushed. - Assess apical pulse rate before administering. ### Hydralazine: - **Direct vasodilator, relaxes vascular smooth muscle.** ### ACE Inhibitor - Captopril: - **Mechanism:** Blocks conversion of Angiotensin I to Angiotensin II. - **Indications:** Treats hypertension, heart failure. - **Nursing Considerations:** - Contraindicated in pregnancy. - Use with caution in diabetic patients. ### Respi additional Notes - **Montelukast** is approved for use in children as young as 6 months of age and older for the treatment of asthma. - **Fluticasone nasal spray formulations**, for the treatment of allergic rhinitis, are often approved for use in children aged 2 years and older. ### GI additional notes - This harmless but temporary side effect, known as "black hairy tongue," can occur with the use of bismuth subsalicylate and may cause discoloration of the tongue. It’s essential for patients to be aware of this potential effect to prevent unnecessary concern.